Update, more or less...
I managed to buy a r9-290 somehow.
It looks like this https://www.newegg.com/powercolor-radeon-r9-290-axr9-290-4gbd5-tdhe-oc/p/N82E16814131569.
It is 20mm wider but 8mm shorter than a reference card.
I tried putting the reference cooler on it but it has some weird heat...